1. Field of the Invention
The present invention relates generally to wind energy collectors and, specifically, to an improved wind turbine generator.
2. Description of Related Art
With the concern to conserve energy and to produce energy in the most efficient manner from existing energy sources, there have been numerous designs in the past to provide wind energy collection apparatus. Older designs tended to favor the vertically-disposed, airplane propeller type. More recently, artisans have tended to use a horizontally disposed, turbine type design. An advantage of the horizontal design is the use of an efficient turbine that has a large surface area to interact with and absorb energy from the wind. However, the basic turbine is substantially cylindrical in shape and does not have a preferred operational orientation like the substantially disc-shaped propeller design. That is to say, a propeller interacts maximally when its axis of rotation is directly parallel to the direction of the wind. This orientation is maintained by mounting the axis of rotation horizontally with means to rotate that axis to be parallel to the prevailing wind. On the other hand, a turbine operates maximally when its axis of rotation is perpendicular to the prevailing wind. However, maximal efficiency is attained only when means are provided to direct the prevailing wind to one quadrant of the turbine and shield the other parts of the turbine from the wind. Thus, the turbine is not inherently directional, and the required responsiveness to wind direction is provided not by reorienting the turbine about its vertical axis of rotation, but by redirecting the wind.
For example, Trigilio, U.S. Pat. No. 4,551,631, for "Wind and Solar Electric Generating Plant," provides a plurality of shutter assemblies disposed in a circular relationship around a turbine assembly. Five wall assemblies extend tangentially from the circular periphery defined by the shutter assemblies. Opening and closing appropriate shutters directs the wind to the appropriate parts of the turbine and allows a response to changes in wind direction. Ferencz, U.S. Pat. No. 3,986,785, for "Vertical Axis Wind Motor," uses a plurality of reorientatable deflectors situated annularly around the turbine to direct the wind. Storm, U.S. Pat. No. 4,545,729, for "Wind Turbine Apparatus," provides a plurality of sail elements and a system of weights and cables that change the sail elements in response to changes in the wind. In Storm the directionality is provided by modifying the turbine itself. These inventions permit considerable deflection of the wind and control over changes in the prevailing wind direction, but at considerable expense and mechanical complexity. Binder, U.S. Pat. No. 4,496,848, for "Device for Harnessing Wind Energy Including Shock Absorber," provides a single semicylindrical shield that is rotatable about the turbine. This provides relatively simple control over changes in wind direction, but does nothing to redirect the wind to maximize turbine energy conversion.